The present invention relates to a combing machine having a pair of detachment rolls, and a nipper head which, during a nip, effects a forward stroke towards the pair of detachment rolls as well as a return stroke.
In combing machines which operate in accordance with the Nasmith principle, the web is completely separated and then brought together again during a nip, i.e. during a complete stroke cycle of the nipper. Although the separating by an extensive drawing between defined clamping points does not raise any problem, the bringing together of the web, referred to as "piecing", encounters difficulties.
Piecing is a very important quality feature. Good piecing of the web (top) is characterized by a parallel, stretched position of the fibers, connected with uniform distribution of the fibers in longitudinal and transverse directions.
Good piecing requires an undisturbed application of the starting end of the following fiber structure (i.e. of the fiber tuft) onto the trailing end of the top.
On the one hand, with increasing frequency of stroke of the nipper or with an increasing number of nips, undisturbed piecing becomes more and more difficult. On the other hand, a high number of nips is desired since the production of combed sliver can thus be directly increased. Every spinning mill is confronted by the task of finding a suitable compromise between productivity and quality upon combing.
For reasons of economy, therefore, the highest possible number of nips without disturbing reductions in quality is desirable.